The present invention relates generally to cataract surgery. More particularly, the present invention relates to a supracapsular method of cataract phacoemulsification and an instrument therefor.
A cataract refers to an area or portion of the crystalline lens of an eye that has become opaque. Usually, the cataract, which is contained within a lens capsule, comprises the hardened opaque or cloudy lens portion known as the cataract nucleus surrounded by the softer cortex. Treatment therefor involves removing a portion of the capsule to provide an opening (capsulorrhexis) and removal of the diseased lens through the opening and its replacement within the remaining portion of the capsule with an artificial lens. For the purposes of this specification and the claims, the term xe2x80x9ccataractxe2x80x9d refers to the entire diseased lens.
Cataract removal may be broadly classified as xe2x80x9csupracapsularxe2x80x9d, wherein the cararact is removed from the capsule before phacoemulsification either with or without nuclear disassembly, and xe2x80x9cintracapsularxe2x80x9d, wherein the cataract is phacoemulsified while it remains within the capsule. One supracapsular approach has involved a difficult flipping maneuver known as David Brown""s xe2x80x9cphaco flipxe2x80x9d, wherein the entire lens is xe2x80x9cflippedxe2x80x9d out of the capsule before phacoemulsification. Other supracapsular approaches involve tilting the lens out of the capsule. These difficult approaches include one known as Richard Lindstrom""s xe2x80x9ctilt and tumblexe2x80x9d phaco and a technique attributed to Richard Kratz.
Because of the difficulties of the supracapsular approaches, an intracapsular approach known as the xe2x80x9cdivide and conquerxe2x80x9d method has remained popular. In accordance with this method, referring to FIG. 1 wherein the capsule is illustrated at 20, the capsule opening or capsulorrhexis is illustrated at 22, the diseased lens or cataract is illustrated at 23, the cataract nucleus is illustrated at 24, and the cortex is illustrated at 26, a phaco tip 28 is used to make a groove 30 in the nucleus 24, the cataract rotated 90 degrees, and a second groove 32 made in the nucleus 24. The nucleus 24 is then divided into four quadrants 34 using the phaco tip 28 and a second instrument known as the Bechert nucleus rotator, which is illustrated at 36 in FIG. 13. In the use of this intracapsular method, it is difficult to position the first quadrant for emulsification. Dense cataracts often prove quite difficult to disengage because of significant resistance by the remaining three quadrants, which remain interlocked even though they have been cracked. The surgeon must move one-quarter of the entire nuclear mass against the other 75 percent, a series of maneuvers that require significant force to be directed against the resistance, particularly if residual epinuclear adhesions remain. Four discrete triangular-shaped quadrants translate into 12 pointed areas that clearly increase the potential of a capsular rent if excessive manipulation is required to engage and position each quadrant for emulsification.
It has been suggested that it is more efficient to remove the nucleus from the capsular bag prior to phacoemulsification. In addition, supracapsular methods are considered safer since capsular rupture is exceedingly rare with such methods. It is thus considered desirable to return to a supracapsular method which does not have the difficulties of the supracapsular methods discussed above.
Of interest to the present invention may be U.S. Pat. Nos. 4,676,793; 5,057,098; 5,156,607; 5,451,230; and 5,653,724, which disclose various techniques for cataract surgery and which are hereby incorporated herein by reference.
I have developed and have been successfully using for more than a year an easy to use supracapsular method of cataract removal for soft nuclear cataracts which are found in younger patients, wherein a single deep groove is formed in the nucleus (wherein the two halves remain joined after the groove is formed) and one half is xe2x80x9cflappedxe2x80x9d over onto the other joined half to allow supracapsular phacoemulsification to occur.
The above xe2x80x9cflap and stackxe2x80x9d technique does not work for harder cataracts found in older patients since the forces anchoring the two cataract portions together causes resistance to maneuverability of the distal portion. It is therefore considered desirable to provide an efficient and safe supracapsular method, which is also easy to use, for removal of harder cataracts.
The Bechert rotator 36 (FIG. 13) has been used to separate the cataract from the capsule 20 and to otherwise assist in manipulation of the nucleus portions as needed. The rotator 36 is seen to comprise a pair of prongs 38 defining a Y-shape. These prongs 38 may undesirably traumatize the capsule 20.
It is accordingly an object of the present invention to provide an efficient, safe, and easy to use supracapsular method for removal of cataracts.
It is another object of the present invention to provide an instrument for sweeping the lens capsule away from cataract portions and for otherwise assisting in manipulation of nucleus portions wherein the chances of trauma to the capsule are minimized.
In order to provide an efficient, safe, and easy to use supracapsular method for removal of cataracts, in accordance with the present invention, a groove is formed in the cataract nucleus, the nucleus is cracked along the groove into two halves and rotated approximately 90 degrees, force is applied to the proximal half to effect movement of the distal half into a stacked position relative to the proximal half, and the nucleus halves along with the remainder of the cataract are then emulsified and removed.
In order to minimize the chances of trauma to the capsule while sweeping the lens capsule away from cataract portions as well as making a crack in the nucleus and for otherwise assisting in manipulation of nucleus portions, in accordance with the present invention, an instrument is provided which has a prongless portion, preferably with a convex frontal edge, for engaging the cataract.
The above and other objects, features, and advantages will be apparent in the following detailed description of the preferred embodiments of the present invention when read in conjunction with the accompanying drawings wherein the same reference numerals denote the same or similar parts throughout the several views.